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    <title>Document</title>
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    <script>
        // let [a, b, c] = [1, 2, 3, 4]
        // let arr = [1]
        // console.log(c);
        // const fn = v => alert(v);
        // fn(11)
        // const fn = v => console.log(this);
        // fn()
        // const fun = (...item) => console.log(item);
        // fun(4, ...[1, 3, 2])
        // const arr = [1, 2, 3];
        // let [s1, ...s2] = arr;
        // console.log(s1);//1
        // console.log(s2);//2,3
        // s2.push(...arr)
        // console.log(s2);//2,3,1,2,3
        // const obj = {
        //     0: 2,
        //     1: 3,
        //     'length': 2
        // }
        // const arr = Array.from(obj, item => ++item)
        // console.log(arr);
        // let arrayLike = {
        //     0: 'tom',
        //     1: '65',
        //     2: '男',
        //     3: ['jane', 'john', 'Mary'],
        //     'length': 4
        // }
        // let arr1 = Array.from(arrayLike)
        // console.log(arr1)  // ['tom','65','男',['jane','john','Mary']]
        // console.log('s'.repeat(2));
        const xhr = new XMLHttpRequest();
        console.log(xhr);
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